Coal Washery Waste Water Treatment using Natural Coagulants and Chemical Precipitation

During the washing and beneficiation of coal or any minerals, particulates become suspended in waste water. Before reuse of these discharged waters, suspended particulates and various contaminants must be removed from this effluent. Coal washery consume huge amount of water and hence generates huge amount of waste water. If this water is directly discharged into streams, it will cause environmental pollution. Coal washery effluents contain high amount of suspended particles, has high turbidity, and color, besides it contains heavy metals. In this project work, chemical and natural coagulants have been used and comparative study has been made about the effectiveness of chemical and natural coagulants. The present study deals with the evaluation of treatment efficiency of natural coagulants okra seeds and bitter gourd seed, commonly available in market. Primarily the basic parameters-pH, suspended solids, turbidity, heavy metals and coagulant dosage are optimized. Coagulation of seed extract for okra and bitter gourd was assessed by the use of jar test experiment in coal washery effluent with various coagulant doses. About 50 % of turbidity removal was achieved by okra seeds at neutral pH and 62 % at pH between 7-8 and 99.96 % removal efficiency of iron was obtained with bitter gourd seeds.